Shunsuke Mie
2023-Feb-03 10:04 UTC
[RFC PATCH 3/4] PCI: endpoint: Introduce virtio library for EP functions
Add a new library to access a virtio ring located on PCIe host memory. The
library generates struct pci_epf_vringh that is introduced in this patch.
The struct has a vringh member, so vringh APIs can be used to access the
virtio ring.
Signed-off-by: Shunsuke Mie <mie at igel.co.jp>
Signed-off-by: Takanari Hayama <taki at igel.co.jp>
---
drivers/pci/endpoint/Kconfig | 7 ++
drivers/pci/endpoint/Makefile | 1 +
drivers/pci/endpoint/pci-epf-virtio.c | 113 ++++++++++++++++++++++++++
include/linux/pci-epf-virtio.h | 25 ++++++
4 files changed, 146 insertions(+)
create mode 100644 drivers/pci/endpoint/pci-epf-virtio.c
create mode 100644 include/linux/pci-epf-virtio.h
diff --git a/drivers/pci/endpoint/Kconfig b/drivers/pci/endpoint/Kconfig
index 17bbdc9bbde0..07276dcc43c8 100644
--- a/drivers/pci/endpoint/Kconfig
+++ b/drivers/pci/endpoint/Kconfig
@@ -28,6 +28,13 @@ config PCI_ENDPOINT_CONFIGFS
configure the endpoint function and used to bind the
function with a endpoint controller.
+config PCI_ENDPOINT_VIRTIO
+ tristate
+ depends on PCI_ENDPOINT
+ select VHOST_IOMEM
+ help
+ TODO update this comment
+
source "drivers/pci/endpoint/functions/Kconfig"
endmenu
diff --git a/drivers/pci/endpoint/Makefile b/drivers/pci/endpoint/Makefile
index 95b2fe47e3b0..95712f0a13d1 100644
--- a/drivers/pci/endpoint/Makefile
+++ b/drivers/pci/endpoint/Makefile
@@ -4,5 +4,6 @@
#
obj-$(CONFIG_PCI_ENDPOINT_CONFIGFS) += pci-ep-cfs.o
+obj-$(CONFIG_PCI_ENDPOINT_VIRTIO) += pci-epf-virtio.o
obj-$(CONFIG_PCI_ENDPOINT) += pci-epc-core.o pci-epf-core.o\
pci-epc-mem.o functions/
diff --git a/drivers/pci/endpoint/pci-epf-virtio.c
b/drivers/pci/endpoint/pci-epf-virtio.c
new file mode 100644
index 000000000000..7134ca407a03
--- /dev/null
+++ b/drivers/pci/endpoint/pci-epf-virtio.c
@@ -0,0 +1,113 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Virtio library for PCI Endpoint function
+ */
+#include <linux/kernel.h>
+#include <linux/pci-epf-virtio.h>
+#include <linux/pci-epc.h>
+#include <linux/virtio_pci.h>
+
+static void __iomem *epf_virtio_map_vq(struct pci_epf *epf, u32 pfn,
+ size_t size, phys_addr_t *vq_phys)
+{
+ int err;
+ phys_addr_t vq_addr;
+ size_t vq_size;
+ void __iomem *vq_virt;
+
+ vq_addr = (phys_addr_t)pfn << VIRTIO_PCI_QUEUE_ADDR_SHIFT;
+
+ vq_size = vring_size(size, VIRTIO_PCI_VRING_ALIGN) + 100;
+
+ vq_virt = pci_epc_mem_alloc_addr(epf->epc, vq_phys, vq_size);
+ if (!vq_virt) {
+ pr_err("Failed to allocate epc memory\n");
+ return ERR_PTR(-ENOMEM);
+ }
+
+ err = pci_epc_map_addr(epf->epc, epf->func_no, epf->vfunc_no,
*vq_phys,
+ vq_addr, vq_size);
+ if (err) {
+ pr_err("Failed to map virtuqueue to local");
+ goto err_free;
+ }
+
+ return vq_virt;
+
+err_free:
+ pci_epc_mem_free_addr(epf->epc, *vq_phys, vq_virt, vq_size);
+
+ return ERR_PTR(err);
+}
+
+static void epf_virtio_unmap_vq(struct pci_epf *epf, void __iomem *vq_virt,
+ phys_addr_t vq_phys, size_t size)
+{
+ pci_epc_unmap_addr(epf->epc, epf->func_no, epf->vfunc_no, vq_phys);
+ pci_epc_mem_free_addr(epf->epc, vq_phys, vq_virt,
+ vring_size(size, VIRTIO_PCI_VRING_ALIGN));
+}
+
+/**
+ * pci_epf_virtio_alloc_vringh() - allocate epf vringh from @pfn
+ * @epf: the EPF device that communicates to host virtio dirver
+ * @features: the virtio features of device
+ * @pfn: page frame number of virtqueue located on host memory. It is
+ * passed during virtqueue negotiation.
+ * @size: a length of virtqueue
+ */
+struct pci_epf_vringh *pci_epf_virtio_alloc_vringh(struct pci_epf *epf,
+ u64 features, u32 pfn,
+ size_t size)
+{
+ int err;
+ struct vring vring;
+ struct pci_epf_vringh *evrh;
+
+ evrh = kmalloc(sizeof(*evrh), GFP_KERNEL);
+ if (!evrh) {
+ err = -ENOMEM;
+ goto err_unmap_vq;
+ }
+
+ evrh->size = size;
+
+ evrh->virt = epf_virtio_map_vq(epf, pfn, size, &evrh->phys);
+ if (IS_ERR(evrh->virt))
+ return evrh->virt;
+
+ vring_init(&vring, size, evrh->virt, VIRTIO_PCI_VRING_ALIGN);
+
+ err = vringh_init_iomem(&evrh->vrh, features, size, false, GFP_KERNEL,
+ vring.desc, vring.avail, vring.used);
+ if (err)
+ goto err_free_epf_vq;
+
+ return evrh;
+
+err_free_epf_vq:
+ kfree(evrh);
+
+err_unmap_vq:
+ epf_virtio_unmap_vq(epf, evrh->virt, evrh->phys, evrh->size);
+
+ return ERR_PTR(err);
+}
+EXPORT_SYMBOL_GPL(pci_epf_virtio_alloc_vringh);
+
+/**
+ * pci_epf_virtio_free_vringh() - release allocated epf vring
+ * @epf: the EPF device that communicates to host virtio dirver
+ * @evrh: epf vringh to free
+ */
+void pci_epf_virtio_free_vringh(struct pci_epf *epf,
+ struct pci_epf_vringh *evrh)
+{
+ epf_virtio_unmap_vq(epf, evrh->virt, evrh->phys, evrh->size);
+ kfree(evrh);
+}
+EXPORT_SYMBOL_GPL(pci_epf_virtio_free_vringh);
+
+MODULE_DESCRIPTION("PCI EP Virtio Library");
+MODULE_AUTHOR("Shunsuke Mie <mie at igel.co.jp>");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/pci-epf-virtio.h b/include/linux/pci-epf-virtio.h
new file mode 100644
index 000000000000..ae09087919a9
--- /dev/null
+++ b/include/linux/pci-epf-virtio.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * PCI Endpoint Function (EPF) for virtio definitions
+ */
+#ifndef __LINUX_PCI_EPF_VIRTIO_H
+#define __LINUX_PCI_EPF_VIRTIO_H
+
+#include <linux/types.h>
+#include <linux/vringh.h>
+#include <linux/pci-epf.h>
+
+struct pci_epf_vringh {
+ struct vringh vrh;
+ void __iomem *virt;
+ phys_addr_t phys;
+ size_t size;
+};
+
+struct pci_epf_vringh *pci_epf_virtio_alloc_vringh(struct pci_epf *epf,
+ u64 features, u32 pfn,
+ size_t size);
+void pci_epf_virtio_free_vringh(struct pci_epf *epf,
+ struct pci_epf_vringh *evrh);
+
+#endif // __LINUX_PCI_EPF_VIRTIO_H
--
2.25.1
Michael S. Tsirkin
2023-Feb-03 10:20 UTC
[RFC PATCH 3/4] PCI: endpoint: Introduce virtio library for EP functions
On Fri, Feb 03, 2023 at 07:04:17PM +0900, Shunsuke Mie wrote:> Add a new library to access a virtio ring located on PCIe host memory. The > library generates struct pci_epf_vringh that is introduced in this patch. > The struct has a vringh member, so vringh APIs can be used to access the > virtio ring. > > Signed-off-by: Shunsuke Mie <mie at igel.co.jp> > Signed-off-by: Takanari Hayama <taki at igel.co.jp> > --- > drivers/pci/endpoint/Kconfig | 7 ++ > drivers/pci/endpoint/Makefile | 1 + > drivers/pci/endpoint/pci-epf-virtio.c | 113 ++++++++++++++++++++++++++ > include/linux/pci-epf-virtio.h | 25 ++++++ > 4 files changed, 146 insertions(+) > create mode 100644 drivers/pci/endpoint/pci-epf-virtio.c > create mode 100644 include/linux/pci-epf-virtio.h > > diff --git a/drivers/pci/endpoint/Kconfig b/drivers/pci/endpoint/Kconfig > index 17bbdc9bbde0..07276dcc43c8 100644 > --- a/drivers/pci/endpoint/Kconfig > +++ b/drivers/pci/endpoint/Kconfig > @@ -28,6 +28,13 @@ config PCI_ENDPOINT_CONFIGFS > configure the endpoint function and used to bind the > function with a endpoint controller. > > +config PCI_ENDPOINT_VIRTIO > + tristate > + depends on PCI_ENDPOINT > + select VHOST_IOMEM > + help > + TODO update this comment > + > source "drivers/pci/endpoint/functions/Kconfig" > > endmenu > diff --git a/drivers/pci/endpoint/Makefile b/drivers/pci/endpoint/Makefile > index 95b2fe47e3b0..95712f0a13d1 100644 > --- a/drivers/pci/endpoint/Makefile > +++ b/drivers/pci/endpoint/Makefile > @@ -4,5 +4,6 @@ > # > > obj-$(CONFIG_PCI_ENDPOINT_CONFIGFS) += pci-ep-cfs.o > +obj-$(CONFIG_PCI_ENDPOINT_VIRTIO) += pci-epf-virtio.o > obj-$(CONFIG_PCI_ENDPOINT) += pci-epc-core.o pci-epf-core.o\ > pci-epc-mem.o functions/ > diff --git a/drivers/pci/endpoint/pci-epf-virtio.c b/drivers/pci/endpoint/pci-epf-virtio.c > new file mode 100644 > index 000000000000..7134ca407a03 > --- /dev/null > +++ b/drivers/pci/endpoint/pci-epf-virtio.c > @@ -0,0 +1,113 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Virtio library for PCI Endpoint function > + */ > +#include <linux/kernel.h> > +#include <linux/pci-epf-virtio.h> > +#include <linux/pci-epc.h> > +#include <linux/virtio_pci.h> > + > +static void __iomem *epf_virtio_map_vq(struct pci_epf *epf, u32 pfn, > + size_t size, phys_addr_t *vq_phys) > +{ > + int err; > + phys_addr_t vq_addr; > + size_t vq_size; > + void __iomem *vq_virt; > + > + vq_addr = (phys_addr_t)pfn << VIRTIO_PCI_QUEUE_ADDR_SHIFT; > + > + vq_size = vring_size(size, VIRTIO_PCI_VRING_ALIGN) + 100;100? Also ugh, this uses the legacy vring_size. Did not look closely but is all this limited to legacy virtio then? Pls make sure you code builds with #define VIRTIO_RING_NO_LEGACY.> + > + vq_virt = pci_epc_mem_alloc_addr(epf->epc, vq_phys, vq_size); > + if (!vq_virt) { > + pr_err("Failed to allocate epc memory\n"); > + return ERR_PTR(-ENOMEM); > + } > + > + err = pci_epc_map_addr(epf->epc, epf->func_no, epf->vfunc_no, *vq_phys, > + vq_addr, vq_size); > + if (err) { > + pr_err("Failed to map virtuqueue to local"); > + goto err_free; > + } > + > + return vq_virt; > + > +err_free: > + pci_epc_mem_free_addr(epf->epc, *vq_phys, vq_virt, vq_size); > + > + return ERR_PTR(err); > +} > + > +static void epf_virtio_unmap_vq(struct pci_epf *epf, void __iomem *vq_virt, > + phys_addr_t vq_phys, size_t size) > +{ > + pci_epc_unmap_addr(epf->epc, epf->func_no, epf->vfunc_no, vq_phys); > + pci_epc_mem_free_addr(epf->epc, vq_phys, vq_virt, > + vring_size(size, VIRTIO_PCI_VRING_ALIGN)); > +} > + > +/** > + * pci_epf_virtio_alloc_vringh() - allocate epf vringh from @pfn > + * @epf: the EPF device that communicates to host virtio dirver > + * @features: the virtio features of device > + * @pfn: page frame number of virtqueue located on host memory. It is > + * passed during virtqueue negotiation. > + * @size: a length of virtqueue > + */ > +struct pci_epf_vringh *pci_epf_virtio_alloc_vringh(struct pci_epf *epf, > + u64 features, u32 pfn, > + size_t size) > +{ > + int err; > + struct vring vring; > + struct pci_epf_vringh *evrh; > + > + evrh = kmalloc(sizeof(*evrh), GFP_KERNEL); > + if (!evrh) { > + err = -ENOMEM; > + goto err_unmap_vq; > + } > + > + evrh->size = size; > + > + evrh->virt = epf_virtio_map_vq(epf, pfn, size, &evrh->phys); > + if (IS_ERR(evrh->virt)) > + return evrh->virt; > + > + vring_init(&vring, size, evrh->virt, VIRTIO_PCI_VRING_ALIGN); > + > + err = vringh_init_iomem(&evrh->vrh, features, size, false, GFP_KERNEL, > + vring.desc, vring.avail, vring.used); > + if (err) > + goto err_free_epf_vq; > + > + return evrh; > + > +err_free_epf_vq: > + kfree(evrh); > + > +err_unmap_vq: > + epf_virtio_unmap_vq(epf, evrh->virt, evrh->phys, evrh->size); > + > + return ERR_PTR(err); > +} > +EXPORT_SYMBOL_GPL(pci_epf_virtio_alloc_vringh); > + > +/** > + * pci_epf_virtio_free_vringh() - release allocated epf vring > + * @epf: the EPF device that communicates to host virtio dirver > + * @evrh: epf vringh to free > + */ > +void pci_epf_virtio_free_vringh(struct pci_epf *epf, > + struct pci_epf_vringh *evrh) > +{ > + epf_virtio_unmap_vq(epf, evrh->virt, evrh->phys, evrh->size); > + kfree(evrh); > +} > +EXPORT_SYMBOL_GPL(pci_epf_virtio_free_vringh); > + > +MODULE_DESCRIPTION("PCI EP Virtio Library"); > +MODULE_AUTHOR("Shunsuke Mie <mie at igel.co.jp>"); > +MODULE_LICENSE("GPL"); > diff --git a/include/linux/pci-epf-virtio.h b/include/linux/pci-epf-virtio.h > new file mode 100644 > index 000000000000..ae09087919a9 > --- /dev/null > +++ b/include/linux/pci-epf-virtio.h > @@ -0,0 +1,25 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* > + * PCI Endpoint Function (EPF) for virtio definitions > + */ > +#ifndef __LINUX_PCI_EPF_VIRTIO_H > +#define __LINUX_PCI_EPF_VIRTIO_H > + > +#include <linux/types.h> > +#include <linux/vringh.h> > +#include <linux/pci-epf.h> > + > +struct pci_epf_vringh { > + struct vringh vrh; > + void __iomem *virt; > + phys_addr_t phys; > + size_t size; > +}; > + > +struct pci_epf_vringh *pci_epf_virtio_alloc_vringh(struct pci_epf *epf, > + u64 features, u32 pfn, > + size_t size); > +void pci_epf_virtio_free_vringh(struct pci_epf *epf, > + struct pci_epf_vringh *evrh); > + > +#endif // __LINUX_PCI_EPF_VIRTIO_H > -- > 2.25.1